a drop in the ocean

• 沧海一粟；九牛一毛

a drop in the ocean的用法和样例：

例句

1. Human history is merely a drop in the ocean.
   人类的历史仅是沧海一粟。
2. For him the loss was only a drop in the ocean.
   这点损失对他来说，只不过是九牛一毛。